The present invention relates to engine starters, and particularly to starters for model engines. More particularly, the present invention relates to hand-held starters for model engines used in model helicopters, airplanes and cars.
Model engines, such as those commonly used on model airplanes, typically do not include an automatic starting feature, but are sometimes started by hand. Manual starting requires a skilled operator, and is often difficult if the model engine is not properly adjusted. Hand-held electric starter motors are now in widespread use and make starting a model engine much easier. These devices typically consist of a high-torque electric motor held in the palm of the operator""s hand and actuated by a finger switch. Such devices are applied to an output shaft of the model engine to turn the model engine at high speed while the operator performs appropriate engine starting procedures. Once the model engine is running, the electric starter motor is disconnected from the engine and set aside.
The minimum amount of torque that a starter motor must produce to start a model engine is generally dictated by the size of the model engine with which the starter motor is used. Traditional hand-held starters are bulky and cumbersome, partly because they are sized to start large model engines, and partly because the finger switch of these starters is commonly located on the motor housing itself thereby increasing the effective diameter of the motor and the associated hand-grip diameter. Large diameter starters are not well suited for use by operators with small hands such as children or teenagers.
Most commercially available starters are designed to start model engines of 0.10 cubic inch displacement to 0.60 cubic inch displacement and are called xe2x80x9cstandardxe2x80x9d or xe2x80x9cmediumxe2x80x9d starters. Starters capable of starting up to about 1.5 cubic inch displacement engines are termed xe2x80x9chigh torquexe2x80x9d starters. Medium and high torque starters generally operate at relatively low rotational speeds of between 3000 revolutions per minute (RPM) and 6000 RPM, which is too slow to easily start small model engines below 0.10 cubic inch displacement. Such small model engines start more easily when turned at a high speed of 10,000 RPM to 15,000 RPM.
As populations increase and recreational sites become scarce, smaller models and model engines are becoming more popular. These small models are suitable for younger modelers who have small hands and who cannot comfortably operate a large electric starter. What is needed is a hand-held starting device suitable for small engines and adapted for use by operators with small hands as well as by operators with large hands.
According to the present disclosure, a hand-held starter apparatus for starting model engines includes a motor, a body supporting the motor, a switching device that activates the motor, and a trigger in communication with the switching device. The body is configured for comfortable gripping by users with large hands and by users with small hands.
In preferred embodiments, the motor is a high-speed starter motor having a shaft that rotates about a motor rotation axis and having an adapter assembly that is coupled to the shaft and that is configured to couple to an engine shaft of a model engine to transfer rotational motion from the starter motor to the model engine. In an illustrative embodiment, the body has a front portion which is generally circular in cross-section near the starter motor and a rear portion which is generally elliptical or oval in cross-section to more comfortably accommodate the small (xe2x80x9cringxe2x80x9d and xe2x80x9cpinkyxe2x80x9d) fingers of the operator""s hand. The trigger switch is preferably located behind the starter motor to minimize the diameter of the body adjacent to the starter motor. The trigger extends from the body in a forward direction over the motor and is actuated by the fingers or palm of the operator""s hand.
According to this disclosure, the body includes a forward ridge and a rear ridge to axially position the operator""s hand during operation of the hand-held starter apparatus. A front guard is provided to protect against accidental finger injury during starting of a model engine and to prevent accidental depression of the trigger when the hand-held starter apparatus is placed on a hard, flat surface such as the ground or a table after use.
In contrast to existing hand-held industrial motors such as electric and air powered die grinders which are generally cylindrical, the illustrative body narrows and is configured to accommodate the small fingers of the hand and support the hand grip of the operator against axial force, such as the force required to hold the starter motor against a shaft of a model engine during starting. The illustrative body is suitable for use in a vertical orientation where the axial holding features of the body provide a positive hand-hold against gravity even when the exterior of the device is coated with slippery engine exhaust oil from a model engine.
When equipped with a high-speed 10,000 RPM to 15,000 RPM motor, the starter apparatus of the present disclosure is ideally suited to start small engines of less than 0.10 cubic inch displacement. Furthermore, the illustrative apparatus is small and maneuverable enough to be used as a hobby tool in addition to a model engine starter, and an adapter is provided to accommodate commercially available rotary cutting and grinding tools. An alternative portable embodiment having an on-board battery is also shown and described in this disclosure.
This disclosure, therefore, relates to a hand-held starting device for model engines, and particularly, to a hand-held starter motor that can be rotationally coupled to a model internal combustion engine to impart rotational motion to the model engine to induce the model engine to start and continue operating under its own power. The illustrative apparatus is suitable for starting model airplane, car, helicopter, and boat engines and is configured to be operated by operators whose hands are generally smaller than those of adults. Thus, the disclosed apparatus is uniquely configured to accommodate small hands safely and comfortably. The disclosed apparatus alternatively can be configured to operate as a portable rotary hand-tool.